Gesture-based user interface

ABSTRACT

The invention includes methods, systems, computer program products and means for providing an intuitive user interface for interacting with a game console that obviates the need for, or use of, a typical game controller. In one embodiment, the user interface comprises an analog-like mechanism for manipulating a menu and icon system. The menu system allows the user to highlight a menu option or icon using movement along one axis and to activate the menu option or icon via movement on a different axis. In one embodiment, highlighting is associated with a vertical motion and activation is associated with a horizontal motion. The vertical motion can be tied to the vertical movement of a particular appendage, e.g., the up and down movement of the user&#39;s right arm, and the horizontal motion can be tied to the horizontal movement of that or another appendage, e.g., movement of the right arm or hand across the body from right to left.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to application Ser. No. 12/913,493, filed on Oct. 27, 2010 and entitled “Gesture-Based User Interface” by Challinor, et al, which claims benefit of priority to Application No. 61/255,462, filed on Oct. 27, 2009 and entitled “Gesture-Based User Interface” by Challinor et al, all of which are incorporated by reference herein in their entirety.

FIELD OF THE INVENTION

The present invention relates generally to gesture-based interfaces and, more specifically, to using gestures to control a video game interface.

BACKGROUND

Although video games and video game consoles are prevalent in many homes, game controllers, with their myriad of buttons and joysticks, are still intimidating and confusing to people that do not often play video games. For these people, using a game controller to interact with the game is an obstacle to enjoying it.

To increase a user's feeling of immersion in the game, as well as to overcome the cumbersome nature of game controllers for users not familiar with them, some game platforms forego the use of traditional controllers and utilize cameras instead. The cameras detect a user's physical movements, e.g., the waving of his arm or leg, and then interpret those movements as input to the video game. This allows the user to use a more natural-feeling input mechanism he is already familiar with, namely the movement of his body, and removes the barrier-to-entry caused by the many-buttoned controller.

One example of a camera-based controller is the EyeToy camera developed by Logitech and used with the Sony PlayStation 2 game console. The EyeToy, and similar cameras, typically include a camera and a microphone. The EyeToy sends a 640×480 pixel video stream to the PlayStation, and the game executing on the PlayStation parses the frames of the video, e.g., calculating gradations of color between pixels in the frame, to determine what in the camera's field-of-view is the user (“player”) and what is the background (“not player”). Then, differences in the stream over time are used to determine and recognize the user's movements, which in turn drive the user's interaction with the game console.

Other cameras used by game platforms include the DreamEye for the Sega Dreamcast, The PlayStation Eye (a successor to the EyeToy) for Sony's PlayStation 3, and the Xbox Live Vision for Microsoft's Xbox 360. These cameras all provide a typical single-input camera that can stream video or take still photographs, and some, such as the PlayStation Eye, additionally provide a microphone for audio input.

Microsoft is currently developing a depth-aware camera system in the form of Project Natal. A Natal system provides an RGB camera, a depth sensor, a multi-array microphone, and software that processes the inputs from the camera, depth sensor, and microphone. Beneficially, the Natal software generates, based on the input, a skeleton that roughly maps to the user's body. Specifically, rather than just determining a difference between “player” and “not player” like prior game cameras, Natal determines what is the user's right hand, left hand, head, torso, right leg, and left leg. This skeleton is preserved as a user moves his body in the camera's field of view, allowing for the tracking of specific limbs. This skeleton framework, however, is the extent of what Natal provides. Namely, no user interface is provided by Natal, and users must still use a game controller to interact with a game or menu system.

Other systems, based on non-camera technologies, have also been developed that attempt to track a user's movements. For example, the Nintendo Wii provides players with an infrared transmitter “Wii remote” that the user holds in his hand. The Wii remote is used as pointing device and has a built-in accelerometer to track changes in the Wii remote's position. The Wii remote is often paired with a “nunchuk” (which also has an accelerometer) that is held in the player's other hand, allowing the Wii to, in a sense, track the movements—or at least changes in the movements—of the user's hands. Another technology based on a hand-held controller is sixense, which is demonstrated at http://www.sixense.com

High-end motion capture (“mo-cap”) systems have also been used to track a user's movements. Typically mo-cap systems involve the user wearing a body suit that has dozens of white spheres located at relevant locations. The mo-cap cameras detect these spheres and use them to infer positional information about the user's body. Mo-cap systems, however, are expensive and not practical for the average user.

SUMMARY OF THE INVENTION

The invention includes methods, systems, computer program products and means for providing an intuitive user interface for interacting with a game console that obviates the need for, or use of, a typical game controller. Though Natal is used as an example herein, the invention is not limited to a Natal implementation.

In one embodiment, the user interface comprises an analog-like mechanism for manipulating a menu and icon system. The menu system allows the user to highlight a menu option or icon using movement along one axis and to activate the menu option or icon via movement on a different axis. In one embodiment, highlighting is associated with a vertical motion and activation is associated with a horizontal motion. The vertical motion can be tied to the vertical movement of a particular appendage, e.g., the up and down movement of the user's right arm, and the horizontal motion can be tied to the horizontal movement of that or another appendage, e.g., movement of the right arm or hand across the body from right to left. Other combinations of arm, leg, and body movements such as waving, kicking, head bobbing, etc., to achieve highlighting or activation would be appreciated by one skilled in the art.

Advantageously, the interface behaves similarly for a short person and a tall person relative to their own bodies. In one embodiment of the invention, appendage and body position determinations are made based on, and relative to, the skeleton of the person interpreted by the system, not on an absolute coordinate system within the camera's field of view. Other variations can utilize an absolute coordinate system to infer information about the user's body.

Typically, ranges are used to control the user interface because motion-tracking input is inherently noisy. Determining precisely where a user's appendages are is difficult due to the natural movement of the user over time and the lag between receiving camera input and processing it. Therefore, the menu system trains users to make gestures large enough—and therefore unambiguously different enough—to compensate for the noise, which simultaneously provides the benefit of eliminating false positives when determining what the user is attempting to accomplish.

In addition to providing an analog-like menu highlighting and activation process, the invention provides an intuitive means of scrolling additional menu options into the menu area visible to the user. Beneficially, this allows for a coarse-grained selection process for a long list of menu options which can then be refined into a fine-grained selection process among the options that have been scrolled into the menu area. In the scenario where there are many more choices than available slots in the main menu, certain spatial positions of the user's appendage in relation to the interpreted skeleton are reserved for navigating or scrolling quickly to menu choices that are far outside the range of the ones currently presented. In these cases, scrolling speed can be varied in accordance with the position of the user's appendage. For example, if the user moves his arm slightly above the position that corresponds to the top of the menu, new options scroll into the menu slowly. If the user raises his arm even higher, new options scroll into the menu more quickly.

The invention also provides an intuitive system for navigating back in a choice hierarchy. Specifically, where menu highlighting and activation are controlled by one appendage, navigating “back” is accomplished by reading the input associated from another appendage and dedicating input from that appendage to the back functionality. For example, in the scenario described above, the menu highlighting and activation are driven using the user's right hand or arm. Back navigation can then correspond to movement of the user's left hand, for example moving across the body from left to right.

The menu system provided herein is beneficial in that it can provide continuous visual and aural feedback to train the user to make unambiguous gestures. Separating the menu navigation into movements that are unambiguous, and in some embodiments combined with hysteresis, accounts for, and overcomes, the visual noise inherent in camera-based and other movement-interpretive systems.

In one embodiment, there is a method, executed on a game platform, for interacting with a menu system displayed on a display in communication with the game platform, based on input received via a sensor. The method and the components it interacts with can also be expressed as a system, in the form of a computer program product, or as an apparatus with means for accomplishing the interaction, where the structures correspond to those previously described, e.g., a display, a game platform, and a sensor (e.g., a camera). The method includes displaying a menu on the display with menu items, receiving a 3D skeleton with a set of two or more joints associated with a first spatial position of two or more reference points on a player's body; and providing interaction based on the 3D skeleton. For example, a scale vector is generated based on two or more of the joints of the 3D skeleton within the set of two or more joints and the scale vector is projected onto an axis. A range of values is assigned to the projected scale vector based on the two or more joints of the 3D skeleton and a value to is assigned to a joint, within the set of two or more joints, such as the wrist. This joint is associated with a highlighting action, and the value assigned to the joint is with respect to the range of values assigned to the projected scale vector. For example, if the projected scale vector is assigned a range from 0.0 to 1.0, the wrist can be assigned a 1.0 is it is at shoulder height, or a 1.5 if above shoulder height, or a 0 if at the user's side. A range of values is assigned to each menu item, with the range of values also being with respect to the range of values assigned to the projected scale vector. For example, one menu item may be assigned 0.0 to 0.2, another may be 0.21 to 0.4, and so on. These are just examples, and the ranges assigned to each are not limited to those described herein. Then, the value of the joint associated with the highlighting action is compared to the range of values of each menu item to determine a highlighted menu item, which is then indicated on the display as the highlighted menu item.

In one version, there is a method for interacting with a menu system displayed on a display in communication with the game platform, which is based on input received via a camera. This method and the components it interacts with can also be expressed as a system, in the form of a computer program product, or as an apparatus with means for accomplishing the interaction, where the structures correspond to those previously described, e.g., a display, a game platform, and a sensor (e.g., a camera). The method involves displaying a menu on the display comprising menu items, receiving a 3D skeleton with joints associated with at least one of the player's shoulders, a lower torso area of the player, and at least one of the player's wrist, and providing interaction with the menu based on these. This is accomplished by first generating a scale vector based on the distance between the 3D skeleton's shoulder joint and an approximation of the player's pelvis and then projecting the scale vector onto an axis. Then, a range of values is assigned to the projected scale vector based on the joint associated with the player's shoulder and on the approximation of the player's pelvis. Next (although the steps can be performed in any order) a value is assigned to a wrist joint, which is associated with a highlighting action. The value that is assigned to the wrist joint is with respect to the range of values assigned to the projected scale vector. A range of values is then assigned to each menu item, with the range of values assigned to each menu item also being with respect to the range of values assigned to the projected scale vector. Then, the value of the wrist joint is compared to the range of values of each menu item to determine a highlighted menu item; and then that menu items is indicated on the display as being highlighted.

In one embodiment, there is a method, executed on a game platform, for interacting with a menu system displayed on a display in communication with the game platform, based on input received via a sensor. The method and the components it interacts with can also be expressed as a system, in the form of a computer program product, or as an apparatus with means for accomplishing the interaction, where the structures correspond to those previously described, e.g., a display, a game platform, and a sensor (e.g., a camera). The method begins by receiving a 3D skeleton having a set of one or more joints associated with a first spatial position of one or more reference points on a player's body. Then, a first direction of potential movement is associated with a highlighting action and a second direction of potential movement, different than the first direction, is associated with an activating action. The first and second directions are greater than or equal to a first threshold difference in degrees with respect to a common axis and are less than or equal to a second threshold difference in degrees with respect to the common axis, e.g., the first threshold difference is 75 degrees and the second threshold difference is 105 degrees (alternatively, both are ninety degrees so the movements are perpendicular to each other). Then, a first spatial position of a joint within the set of one or more joints is determined. Next, one or more updated versions of the 3D skeleton are received, and a second spatial position of the joint is determined based on the one or more updated versions of the 3D skeleton. Then based on the first and second spatial positions of the joint, it is determined if the joint has moved in the direction associated with the highlighting action or in the direction associated with the activation action. After determining this, the action indicated by the movement of the joint is performed. Beneficially, if the joint has moved in the direction associated with the activation action, a change associated with the highlighting action, e.g., highlighting a menu item, is prevented.

There is also a method, executed on a game platform, for interacting with a menu system displayed on a display in communication with the game platform, based on input received via a sensor. The method and the components it interacts with can also be expressed as a system, in the form of a computer program product, or as an apparatus with means for accomplishing the interaction, where the structures correspond to those previously described, e.g., a display, a game platform, and a sensor (e.g., a camera). The method begins by displaying a menu on the display comprising menu items. Then a 3D skeleton is received that has a set of one or more joints associated with a first spatial position of one or more reference points on a player's body. A range of values is assigned to each menu item, the range of values assigned to each menu item being based on each menu item's respective position. Next, a value is assigned to a joint within the set of one or more joints (the joint is associated with a highlighting action), the value assigned to the joint being based on the joint's position. Then, the value of the joint is compared to the range of values of each menu item to determine a highlighted menu item; and that menu item is highlighted on the display.

Alternatively or additionally, there is also a method, executed on a game platform, for interacting with a menu system displayed on a display in communication with the game platform, based on input received via a sensor. The method and the components it interacts with can also be expressed as a system, in the form of a computer program product, or as an apparatus with means for accomplishing the interaction, where the structures correspond to those previously described, e.g., a display, a game platform, and a sensor (e.g., a camera). The method starts by receiving a 3D skeleton with a set of one or more joints associated with a first spatial position of one or more reference points on a player's body. Then a first spatial position of a joint in the set of one or more joints is determined, and an initial positional value is assigned to the beginning of an activation action based on the first spatial position of the joint. Next, a positional value is assigned to the completion of the activation action, and one or more updated versions of the 3D skeleton are received. Then a second spatial position of the joint is determined based on the one or more updated versions of the 3D skeleton, and it is determined if the second spatial position of the joint corresponds to the positional value assigned to the completion of the activation action. If so, the activation action is executed.

Alternatively, there is a similar method, executed on a game platform, for interacting with a game, displayed on a display in communication with the game platform, based on input received via a sensor. This method and the components it interacts with can also be expressed as a system, in the form of a computer program product, or as an apparatus with means for accomplishing the interaction, where the structures correspond to those previously described, e.g., a display, a game platform, and a sensor (e.g., a camera). The method begins by displaying a scrollable window on the display, the scrollable window having a first set of visual data in it, an area not associated with scrolling a second set of visual data into the scrollable window, and an area associated with scrolling the second set of visual data into the scrollable window. More specifically, in some embodiments, the edges of the window initiate scrolling the second set of data in and the middle of the window does not. The method involves receiving a 3D skeleton with two or more joints associated with a first spatial position of two or more reference points on a player's body. A scale vector is generated based on two or more of the joints of the 3D skeleton within the set of two or more joints, and the scale vector is projected onto an axis. A range of values is assigned to the projected scale vector based on the two or more joints within the set. Then, a value is assigned to a joint within the set of two or more joints, with the joint being associated with a scrolling action. The value assigned to the joint is with respect to the range of values assigned to the projected scale vector. A range of values is then assigned to the area associated with scrolling the visual data, with the range of values assigned to the area also being with respect to the range of values assigned to the projected scale vector. Then the value of the joint associated with the scrolling action is compared to the range of values assigned to the area associated with scrolling the second set of visual data into the scrollable window, and if the value of the joint is within the range assigned to the area associated with scrolling the second visual data into the scrollable window, scrolling the second set of visual data into the scrollable window.

Any of the above embodiments may employ the following additional functionality. The proximity of the value assigned to the joint to the range of values assigned to each menu item may also be indicated on the display. In some versions, the proximity is indicated using graphical indications similar to those used for highlighting, in proportion to the proximity. For example, as the joint gets closer to a menu item, even if not the highlighted menu item, the menu items close by may look like they are partially highlighted, and increasingly so as the joint gets closer. Also, in some embodiments, the range of values assigned to each menu item is a single, different value for each menu item.

In some versions, the axis that is described, and that is associated with a highlighting action, corresponds to an orientation of a menu displayed on the display.

Also, in some embodiments, one or more updated versions of the 3D skeleton can be received, and it is determined if positional information of the one or more updated versions of the 3D skeleton corresponds to the beginning of an activation action. If so, the beginning of the activation action is indicated on the display by altering the highlighted menu item. In some implementation, the activation action comprises movement of a joint in a direction substantially perpendicular to the axis. For example, the activation action can include movement of a joint associated with the activation action at least a first pre-determined distance in a direction substantially perpendicular to the axis and less than a second pre-determined distance in a direction substantially parallel to the axis. And doing so, and thereby completing the activation action, activates the highlighted menu item. Alternatively, the activation action can include movement of a joint associated with the activation action of at least a first distance based on two or more joints in the set of two or more joints of the 3D skeleton, in a direction substantially perpendicular to the axis and less than a second distance in a direction substantially parallel to the axis. This also would complete the activation action and activate the highlighted menu item. In both of these, or any embodiment herein, the joint associated with the activation action is the same joint as the joint associated with the highlighting action.

Beneficially, once the activation action has begun, changes in the value of the joint associated with the highlighting action do not change the highlighted menu item, and, in some implementations, the highlighted menu item is altered (e.g., stretched) in proportion to completion of the activation action. Additionally or alternatively, an audible cue can be played with characteristics in proportion to completion of the activation action.

Also, in some embodiments, the beginning of the activation action ceases to be indicated if the one or more updated versions of the 3D skeleton ceases to correspond to an activation action.

In any of these embodiments referring to two or more joints in the 3D skeleton, the two or more joints that the scale vector is based on can a shoulder joint and a hip joint, or a shoulder joint and a simulated pelvis joint. Any of these joints can be a computed approximation of a joint of the player.

Beneficially, scrolling the menu items that are displayed can be achieved by assigning a range of values to a scroll area, the range of values assigned to the scroll area being with respect to the range of values assigned to the projected scale vector. Then the value of the joint associated with the highlighting action is compared to the range of values assigned to the scroll area, and if the value of the joint is within the range of values assigned to the scroll area, scrolling a different set of menu items onto the display. In some versions, the rate at which the different set of menu items is scrolled onto the display is based on the value of the joint in relation to the range of values assigned to the scroll area. This can be done by assigning a first sub-range of values in the range of values assigned to the scroll area with a slow scrolling operation and assigning a second sub-range of values in the range of values assigned to the scroll area with a fast scrolling operation. Then if the value of the joint associated with the highlight action is determined to be within the sub-range assigned to the slow scrolling operation, scrolling the different set of menu items onto the display at a slow rate. But if the value of the joint associated with the highlight action is determined to be within the sub-range assigned to the fast scrolling operation, scrolling the different set of menu items onto the display at a faster than the slow rate.

There is also, for some versions, hysteresis for the highlighted menu item. This is accomplished by receiving an updated version of the 3D skeleton, assigning a second value to the joint associated with the highlighting action (the value being with respect to the range of values assigned to the projected scale vector) and if the second value is within a range of values assigned to the highlighted menu item, or is within a pre-determined range adjacent to the range of values assigned to the highlighted menu item, continuing to highlight the highlighted menu item. This keeps the current menu item highlighted if the joint has drifted slightly into the area of the next menu item (or the sensor/camera just perceives that due to noise in the input). Additionally, if the second value is not within the range of values assigned to the highlighted menu item and is not within the pre-determined range adjacent to the range of values assigned to the highlighted menu item, highlighted menu item ceases to be highlighted (because the joint has moved sufficiently far away to indicate that the player really meant to de-highlight the previously highlighted item).

Re-targeting is also possible for any of these. This is accomplished by receiving an updated version of the 3D skeleton, with the updated skeleton's set of two or more joints associated with a second spatial position of the two or more reference points on the player's body. Then, the scale vector is updated based on the updated skeleton; and the updated scale vector is re-projecting onto the axis.

Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating the principles of the invention by way of example only.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features, and advantages of the present invention, as well as the invention itself, will be more fully understood from the following description of various embodiments, when read together with the accompanying drawings, in which:

FIG. 1A depicts a game platform with a Project Natal camera system;

FIG. 1B depicts a three-dimensional skeleton provided by Natal;

FIG. 1C shows an embodiment where scale vectors are projected onto a vertical axis;

FIGS. 2A and 2B depict a menu option being highlighted based on the vertical position of the user's hand;

FIG. 3 depicts a menu option in the process of being activated by the user;

FIG. 4 shows a menu where menu option One has been activated;

FIGS. 5A and 5B show one implementation of scrolling; and

FIG. 6 shows activation of the “back” functionality.

DETAILED DESCRIPTION

One embodiment of the present invention is based on the Project Natal framework developed by Microsoft Corporation of Redmond, Wash. As indicated in FIG. 1A, the Project Natal system includes an RGB camera 105, a depth sensor 110, a multi-array microphone 115, and a processor (not shown). The RGB camera 105 delivers a three-color (Red, Green, Blue) video stream to the game console, enabling facial recognition and full-body tracking. The depth sensor 110 is an infrared projector combined with a monochrome CMOS sensor. This allows a game console 120 utilizing Natal to recognize objects in the camera's field of view in three dimensions instead of forcing the game console to parse a two-dimensional video-stream. The multi-array microphone 115 parses voices and sound input, while simultaneously extracting and nullifying ambient noise. Project Natal also features a processor with proprietary software that coordinates the inputs of the Natal system and provides a three-dimensional, skeleton-based system to game developers. Developers can use this system to utilize three-dimensional position information of the joints in the user's body to interact with the game platform. Although Project Natal provides a framework for determining positional information of a user's body, it does not provide an intuitive menu system for controlling the console or games. Although Project Natal is used herein as a framework, the gesture-based user interface is applicable to any system that can interpret input and map it to relevant portions of the screen. While in some embodiments, a camera-based system is used to determine positional information about the user's body in three dimensions, in other embodiments, transducers attached to the user's body are used to detect the movements of the user's limbs. Other embodiments use infrared pointing devices or other motion tracking peripherals. All that is required is a system than can parse movement in two dimensions; adding dimension information from a third dimension, typically depth, simply makes the invention easier to implement due to the additional information provided to the system. In embodiments where the system uses a skeleton, such as Natal, relative body scale mapping is easier to accomplish.

Also shown in FIG. 1A is an exemplary game platform 120. The game platform typically includes a Central Processing Unit (CPU) 125, a graphics processor 130, storage component 135 such as a hard drive, Read Only Memory (ROM) 140, Random Access Memory (RAM) 145, all in signal communication via a bus 150. The bus 150 also connects to an input for the Project Natal System. In some embodiments, the Natal system connects to the game platform 120, e.g., an Xbox 360, via a Universal Serial Bus (USB) connection.

As used herein, the terms “joint”, “bone”, and “skeleton” are intended to have the meaning one of skill in the art of motion capture and animation would ascribe to them. For example, a skeleton can comprise bones, but the number of bones and their positions are a function of the motion capture equipment and the animation rig and do not necessarily correlate to the number and positions of bones in a human skeleton. Similarly, a joint can be at the distal endpoint of a single bone (e.g., a fingertip or the head), and need not be at a point where two bones come together. An example of the Natal skeleton is shown in FIG. 1B. The skeleton generated by the Natal system provides a framework for the dance game, and allows for tracking of not only limbs generally, but specific joints as well. For example, the wrist joint 160 on the right arm is treated separately from the right elbow 165, which is treated differently than the right shoulder 170. Additional portions of the body are also recognized, such as the pelvis, middle of the torso, the head, the neck, and the knees and feet.

An example of the Natal skeleton is shown in FIG. 1B. The skeleton generated by the Natal system provides a framework for the gesture-based user interface, and allows for tracking of not only limbs generally, but specific joints as well. For example, the wrist joint on the right arm is treated separately from the right elbow, which is treated differently than the right shoulder. Additional portions of the body are also recognized, such as the pelvis, middle of the torso, the head, the neck, and the knees and feet.

One of the benefits provided by the skeleton-based system is that the skeletal model can be used to calculate scale vectors based on two or more joints. This provides a spatially relative system, i.e., how far is body part X from body part Y, instead of an absolute coordinate system. FIG. 1C shows one embodiment, where scale vectors 160, 165 are drawn from the mid-pelvis to each shoulder (in a sense forming a “V”). These scale vectors are also three-dimensional and will correspondingly tilt forward, backwards, or sideways depending on the user's posture. These scale vectors are then projected onto a vertical axis to define, for each wrist joint with respect to the user's hip, a range from “at hip height” to “at shoulder height,” typically using values 0.0 to 1.0, respectively. Notably, because the scale vectors are calculated for each side, if a user's shoulders were tilted, as is the case in FIG. 1C, although the physical distance from pelvis to shoulder may differ for each side, the scale value for having either arm at hip height or up at shoulder's height would be the same, even though the wrist joints may be at different heights in an absolute coordinate system. These scale values are also updated constantly so that if a user's posture or body shifts, the system updates accordingly and the system is not locked into an initial reading of the user's body.

In another embodiment, the hip joint is estimated by approximating its position based on the pelvis. In those embodiments, a scale vector starts from each side at the hip and extends to the shoulder joint on that side (i.e., there is a left scale vector from left hip to left shoulder and a right scale vector from right hip to right shoulder). In some embodiments, approximated joint positions (“pseudo-joint” positions) can be used either to set the scale or determine a position within the scale range.

After projecting the scale vectors onto the vertical axis, movement of each arm can be tracked as a scale value on the y axis by determining the y position of the user's wrist joint (indicated by blackened circles in FIG. 1C). The axis runs from the hip to the right shoulder, with the vector describing a range from 0.0 to 1.0 (the numbers used herein are by way of example only and the vector can describe any enumerated range). In this example, 0.0 is the value associated with the user's wrist joint being approximately at hip height and 1.0 being the value for the user's wrist joint at shoulder height. When the user's arm is resting at his side, his wrist joint falls below the hip and is thus interpreted as a negative value. Placing his wrist joint above his shoulder causes the vertical value of his wrist joint to go above 1.0.

Scale values outside the range of the reference points are also useful, e.g., assigning a vector of 2.0 to a wrist joint that is as far above the shoulder as the shoulder is above the pelvis in a 0.0-to-0.1 pelvis/shoulder system. In some embodiments, though, the scales are capped at certain values such that further deviation beyond the cap does not change the scale value. For example, a wrist joint position that is twice as high as pelvis-to-shoulder distance would have a value of 2.0, which is the cap. Any wrist joint position higher is capped and is therefore also 2.0, but the invention is not limited to this embodiment. Although extreme scale values are not used for certain functions, e.g., menu highlighting, the information can be used for other functionalities, e.g., controlling scroll speed.

Other embodiments use hip-to-head measurements, knee-to-shoulder, etc., (pelvis-to-shoulder is merely an example) and the scale vectors can use any enumerated range, linear or non-linear.

Menu Highlighting

FIGS. 2A and 2B depict a menu option (also called a menu item) being highlighted. Interaction with the system begins when the user walks in front of the camera. Initially, the system is in a “release state;” no menu options are highlighted (or, in some embodiments, a default option is highlighted) and the invention is waiting for the user's input. In one embodiment, the release state is characterized by the user's wrist joint being positioned anywhere from at his side to approximately 8 inches in front of his hip. In one embodiment, this is done by determining the Z component of the vector formed from his hip to his wrist joint. In another embodiment, this is done by determining the Z component of the vector formed from his shoulder to his wrist joint. As the user raises his right arm from his side, the invention detects that the user's arm leaves the “dead zone” and begins interpreting the movement and position of the user's right arm as relating to his desired menu choice. The allowance for a dead zone is necessary because not all input is necessarily related to the data displayed on the screen or indicates that the user is trying to interact with the system. Specifically, the user's arms being at his sides could just indicate that he is relaxed. Or, if there is some movement, it could be the user just swinging his arms as he walks. Thus, slight deviation in the user's arm position relative to being directly at his side does not necessarily correspond to a desired menu option.

Once past the dead zone, the position of the user's arm relative to his body is determined, and the menu options highlight correspondingly. To determine which menu option the user is highlighting, each user interface element, here a menu option, has a specific vertical coordinate in the y axis, indicated in FIG. 2A as an “x”. As each menu option is created, the active area for each option extends midway to the next menu option. For example, if the midpoint of each menu option is 10 units from the midpoint of the next menu option, the active area for any given menu option is its y coordinate plus-or-minus five units. The position of the user's wrist joint with respect to the skeletal range is used to determine which menu option the user is highlighting, each option having a value within this range. Based on the vertical component of its location, a menu option is highlighted. As the user moves his arm up and down, his wrist joint changes its scale value, thereby entering and leaving the active area for each menu option. In some implementations, the horizontal aspect of the user's wrist joint is ignored in determining menu highlighting, and highlighting is based entirely on the vertical scale value of the user's wrist joint.

In FIG. 2A, option One is highlighted. Its label “ONE” is presented in yellow (whereas the other menu options are presented in white) indicating that it is the “active” option. The thickness of One's ribbon is greater than that of Two and significantly more so than Three or the others. If the user moves his arm unambiguously into the region of option One, even if the user's arm later drifts into the area for option Two, option One remains highlighted (and subject to activation) until the user's arm has ventured a certain distance into option Two's territory. Although menu highlighting may be presented as continuous, i.e., as the user moves from one menu option to another, the highlighting correspondingly flows from the old choice to the new one, beneficially, the present invention will not change which menu option is actually active to a different menu option until it is clear that the user indeed wants to have the second menu option be the active one. This is accomplished by having hysteresis between menu options.

Hysteresis is useful in preventing oscillation between options when the user is midway between them or is leaving the area of one option and approaching the area of another. The hysteresis zones between options are typically five percent above and below the vertical midpoint between two adjacent menu options, although this is dependent on implementation and more or less allowance for hysteresis can be made. In FIG. 2A, these are represented by the arrows and numbered zones. A hysteresis zone maintains the state of one choice until the user's arm moves a certain distance into another choice. In this example, if the user has highlighted option One (and therefore option One is “active”), he can move his hand into the area of option Two without making Two active (indicated by the bottom of zone 1) although option Two will begin to grow to give feedback to the user that the user's wrist joint is approaching Two's area. If the user makes option Two active, he can then move his arm partially into the area of option One (indicated by zone 2) without activating it. This applies to the other menu options as well, Three (zone 3), Four (zone 4), and so on. By providing feedback to the user that the invention still considers his main choice to be menu option One, if the user really wants menu option Two, the highlighting of both will naturally cause the user to move his wrist joint down to make option Two the active option. Training the user to provide unambiguous input is useful in overcoming the noise inherent in a camera-based system.

Looking now at FIG. 2B, the user has raised his wrist joint so that it is slightly above shoulder height. The system interprets this position information as corresponding only to menu option One, and thus, menu option One is the only one that is highlighted.

Activation

Whereas FIGS. 2A and 2B depict menu option highlighting, FIGS. 3 and 4 depict menu option One in the process of being activated by the usci. In the example used herein, this is accomplished by the user moving his right hand across his body, from right to left. As shown in FIG. 3, the user has moved his wrist joint leftward from in FIG. 2A and the ribbon for option One is correspondingly being pulled leftward. This activation process can be additionally accompanied by an audible sound with an analog component, i.e., that changes with the x position of the wrist joint such as a stretching noise or whoosh, which gives the user an additional indication that he is activating a particular option.

In some embodiments, activation works by tracing (that is, keeping track of) a continuous horizontal line based on the movement of the user's wrist joint along the x axis. If the user breaks the horizontal motion, the activation is released. If however, the horizontal line reaches a specified length, the motion is counted as a gesture. In one embodiment, the required length is approximately 20 inches. Beneficially, less than that length is counted as a partial gesture, proportional to what percentage of that length was reached.

In one embodiment, the horizontal line for activation is calculated differently than the position determination for the wrist joint during highlighting. Instead of determining if a user's wrist is approaching a particular zone, a series of inter-frame vectors are used to determine the movement of the wrist relative to the shoulder. When the wrist has moved a certain amount, the activation is complete.

In this embodiment, the vector from the right shoulder to the right wrist joint is determined for each frame. The equivalent vector from the previous frame is subtracted from the current vector to produce the inter-frame movement vector (to determine how much the wrist moved from frame to frame, relative to the shoulder). Note that each frame measures the position information of both the wrist and the shoulder, so if the user's shoulder is moving in the same direction as the user's wrist—as would be the case if the user were walking sideways—the inter-frame vector would be 0 since the relationship between the user's shoulder and wrist would not change between frames, even though both may have changed horizontal positions in an absolute coordinate system.

The inter-frame vector is then used to determine if the user has completed activation. Due to potential noise in the movement tracking system, if the magnitude of the inter-frame vector is less than a noise threshold, the current frame is skipped. Similarly, if the inter-frame vector is not within 45 degrees of horizontal right-to-left movement, this frame is considered an “error” and is also skipped. If the vector is the first inter-frame vector after an error, the x coordinate of the user's wrist joint is stored as the “initial wrist position” of the gesture. If this is not the first inter-frame vector after an error, the inter-frame vector is considered an interim inter-frame vector. As each interim inter-frame vector is inspected, the “initial wrist position” is subtracted from the x coordinate of the user's wrist joint to determine if the total distance moved exceeds the threshold distance for the gesture (in some embodiments, this distance is about 20 inches). If it has, then the movement is considered an activation.

Optionally, there can be a threshold on the number of errors that can happen before the gesture is released and the “initial wrist position” is cleared.

In some embodiments, the detection of an activation movement, i.e., right to left, locks the user into a menu option, ignoring additional highlighting motions such as up and down, unless the user releases that option by moving his hand left to right, or dropping it to his side before completing the activation motion. Correspondingly, to fully select an option, a user must move his arm from a given horizontal start position at the right of his body to a given horizontal position at the left of his body; he cannot select an option just by placing his right arm in the position that is left of his body. In some embodiments, the distance required for a horizontal motion to be considered a gesture is approximately 20 inches. In some embodiments, locking a user into the activation process occurs only after he has moved a specific minimum distance of the full motion in the horizontal plane, e.g., his wrist joint has traveled approximately 15% of the required distance, or approximately three inches in the examples provided herein. This prevents false positives and overcomes the noise inherent in motion-tracking systems.

Another means of overcoming false positives or false negatives is to give precedence to movement in one axis over movements in a second axis. For example, in one embodiment, if the user tries to indicate activation by moving his hand in a diagonal from close to his right hip up to his left shoulder, the vertical movement is ignored and the horizontal movement is processed as activation. In other embodiments, the opposite is true—horizontal movement is ignored and the diagonal motion is determined to be a change in menu option highlighting. Advantageously, tolerance is provided such that a combination of vertical and horizontal movements in a horizontal plane are interpreted as horizontal, up to a certain deviation of angle or distance from the plane. For example, in some embodiments, the invention accepts a deviation of plus-or-minus three inches, such that moving the user's arm in a slight diagonal swipe across his body from right to left with a total difference in height of six inches from start to finish is still considered a horizontal movement. The same can be applied to a vertical axis; moving horizontally plus or minus eight inches while the user's moves his arm vertically two feet disregards the horizontal input. This allows leeway in the user's interaction such that he does not have to match the designated horizontal or vertical axis exactly. These distances are by way of example only and may be changed based on the implementer's needs.

In some embodiments, however, movement in one plane can negate the input from another plane. Using the example above, if the user is moving his hand horizontally from right to left, but moves his hand vertically outside the tolerance zone of plus-or-minus three inches for the horizontal plane his hand position is associated with, e.g., he moves his hand vertically ten inches, the horizontal motion (activation) is considered negated and the menu system resets to a release state (or highlighting state if the user moves his hand back to a recognized vertical orientation).

Also in FIG. 3, menu option Two is also somewhat highlighted, but not as prominently as menu option One. As described above, this is indicative that the user's arm position is drifting into the area associated with menu option Two, but is not quite unambiguous enough to indicate that menu option Two is really what the user wants. Rather than highlighting one choice that corresponds to the absolute position of the user's arm, the user interface provides feedback that a user is moving from one menu option to another by “flowing” the highlighting from one menu option to the next according to the movements of the user's appendage. For example, assuming a user's right arm is at his side and is presented with five menu choices arranged vertically, as shown in FIGS. 2A, 2B, 3, and 4, as the user moves his arm up, the menu options are highlighted accordingly, first option Five, then Four, etc., until menu option One is highlighted. If the user drops his arm slightly, then option Two becomes slightly highlighted as well.

FIG. 4 shows the completion of menu option One being completely activated. One is a different color (red) than the other menu options and the ribbons for each option are now all narrow. Additionally, referring to the skeleton, his right wrist joint indicates that the user's wrist joint has crossed his body. Once the option is committed to, in this scenario, if the user moves his right hand up or down, or side to side, no input is registered since he has committed to menu option One and the invention is in the process of moving to the next menu screen or workflow based on the activation (or starting the game, etc, depending on what choice was activated). Beneficially, this prevents the invention from reading a very long gesture as two consecutive gestures. To go back to the menu highlighting and activation area, the user must swipe his left hand from left to right to activate the back functionality.

As stated above, the interpretation of the user's movements is not a binary determination. An option is not fully highlighted or activated until the user commits to the corresponding action. This allows a user to release a choice or change his mind mid-activation. As an example, a user may begin activating a particular menu option by moving his right arm from right to left, decide that he does not want that menu option, move his arm in the opposite direction or release his arm to a neutral horizontal position, then highlight a different menu option by moving vertically, and then use a horizontal swipe from right to left across the body for the activation.

Training users to make unambiguous indications is useful in overcoming noise in the motion-tracking system. To reinforce this training, in one embodiment, a release state is entered if the user does not commit to activation within a certain period of time. But the system cannot punish a user too much for being ambiguous because, in a sense, the limitations of the input mechanism are not the user's fault. Therefore, in other embodiments the invention does not require a horizontal activation movement to be completed within a given time frame. In embodiments where the activation process is based on the horizontal line drawn by the user's wrist joint, the user may complete the action as slowly as he wishes, or even stop midway and then continue, as long as he does not deviate too far in the vertical direction or reverse directions too far, which would trigger a release state (although reversing direction slightly indicates the beginning of a release, thereby giving visual feedback to the user that activation is like a spring). In these embodiments, if the total distance travelled right to left is less than 15% of the target distance, the activation is released.

Tutorial on Highlighting and Activation

Gestures that indicate the user's intent are simple for the user to understand and execute once they have been taught to the user. Gestures can be taught using screens that require the user to execute one or more gestures successfully in order to navigate away from the screen. For example, a tutorial screen for highlighting and activation can require a highlight gesture followed by an activation action in order to navigate away from the screen. Similarly, a tutorial screen for scrolling can require that the user scroll a target item into place in order to navigate away from the screen.

In addition, these screens can provide hints as to what sequence motions the user must make to complete the gesture. For example, in one implementations, there is a tutorial screen for highlighting and activation, where the movement associated with highlighting is vertical movement and the movement associated with activation is horizontal movement (where the right wrist is the appendage being tracked). When the user enters the screen, the screen indicates that the user must first execute a highlight gesture with his right wrist. This can be indicated by projecting the view from the camera onto part, or all, of the screen. In some embodiments, the image is reversed left to right so the result is as if the user is looking into a mirror. Then the skeleton is used to locate the right wrist in three-dimensional space, and this is projected into screen space to align with an image associated with the user's right wrist. An indicator can be drawn on the screen over an image associated with the right wrist, for example a circle can be drawn around the on-screen wrist, or around a cursor that represents the movement of the wrist. In some embodiments another indicator is drawn over the desired destination of the gesture. For example, a circle can be placed on the screen at the desired destination of the right wrist. In some embodiments, the two indicators are drawn in a complementary way that indicates that the two positions are linked. For example, the system might draw an empty circle around the user's wrist and a solid circle at the point where the user should move their wrist, or the an empty circle where the user is supposed to move his wrist, and a solid circle around the user's wrist. In some embodiments, the two indicators are joined in some way that indicates the linkage. For example, a line can be drawn between the wrist and the destination of the wrist. In some embodiments, and arrow can be drawn to indicate the direction the wrist should be moved.

Continuing with the example of highlighting and activation, once the system determines that the user has learned the highlighting action, or once the highlighting action is complete, the tutorial can train the user to provide an activation action. In some embodiments, the indicator for the target of the highlighting gesture, and any lines or arrows between the wrist and the target position, can be removed once the highlighting action is complete. A new indicator for the target of the activation action can be drawn, and connected to the wrist indicator using lines and arrows, as described above. In some embodiments, the indicators change depending on the gesture being trained. For example, the circles in the highlighting portion of the tutorial can be replaced by arrows pointing to the user's left when the user begins the activation portion of the tutorial.

Still considering the example of highlighting and activation, audio and visual feedback can be used to indicate to the user his progress towards completing the gesture. For example, a sound can be played that is modified in pitch or speed, based on the distance between the wrist and the target. For example, as the user's wrist gets closer to the target, the sound can go up in pitch, and as the user's wrist gets farther away from the sound—as would be the case in the user “releasing” the action—the sound could go down in pitch. Similarly, the colors or textures of the indicators or lines or arrows can be modified based on the distance between the wrist and the target, e.g., glow brighter as the wrist approaches completion, get dimmer are the wrist releases.

In some embodiments, a tutorial is a separate interface in the game. In some embodiments, a tutorial is embedded in the game as the first screen in which the user can navigate using gestures.

Variations for Highlighting and Activation

Highlighting and activation are not limited to the embodiments described above. In some embodiments, highlighting can be associated with the horizontal movement of one arm and activation can be associated with the horizontal movement of the other arm. Alternatively, highlighting can be associated with horizontal movement of an arm and activation associated with vertical movement of the same arm. In still other embodiments, activation and highlighting are both vertical actions, each performed using different arms. Highlighting and activation are not limited to just horizontal or vertical movements; other movements can be used to highlight and activate in other embodiments, e.g., diagonal swipes, circular motions, motions of pulling the user's hand towards the user or pushing it away from the user, left-to-right, right-to-left, up-to-down, down-to-up, and the like. The key is to have the highlighting and activation gestures be unambiguously different from one another, such that a movement-tracking system can distinguish between them.

Activation may also be accomplished using a form of “dead reckoning,” i.e., accumulating movements over a certain distance threshold until the gesture is completed or released. Specifically, the invention determines a vector of the wrist joint position between two frames (a frame is the data captured at one moment in time; inter-frame calculations—or calculations between two frames—are those involving data from two different moments in time). The distance the wrist joint has moved is compared to a movement threshold, e.g., 2 inches. If the wrist has not moved more than the movement threshold, the inter-frame calculation is discarded (this allows the user to stop gesturing halfway through the motion and then continue the motion to completion). If it has, the angle of the movement is then compared to an angle threshold to determine whether the movement is sufficiently in the expected direction. In one embodiment where activation is right-to-left movement, the angle threshold is plus or minus 45 degrees of the x-axis (where the x-axis is considered to increase from right to left). In other words, the user's wrist is considered to be moving horizontally, right-to-left, if the inter-frame vector has an angle that is within plus or minus 45 degrees of the x-axis. If the wrist movement satisfies the above conditions, the dot product of the inter-frame vector with the unit vector parallel to the x-axis is accumulated until the magnitude of the vector from the first recorded wrist joint position to the last recorded wrist joint position is greater than or equal to the specified length. When it is, the gesture is considered an activation.

In some embodiments, activation is not determined by how far along the x-axis the user's wrist has moved. Instead, the position of the user's activating wrist is used, relative to one of the user's shoulders. Specifically, the shoulder-to-shoulder vector is projected onto the x-axis and a vertical plane, perpendicular to the x axis and running through the user's opposite-side shoulder, is established. In the embodiment where the right hand, moving right to left triggers activation, the position of the right wrist is compared to the plane running through the user's left shoulder. When the user's wrist joint crosses the vertical plane, the active item is activated.

In some embodiments of the invention, animation corresponding to the user's movements is continuous, that is, highlighting flows from one option to another, can run in either direction, e.g., up or down, or left and right for activation, and the movements reflected are in proportion to the user's movements, i.e., quick movement result in quick highlighting changes, slow movements are reflected slowly. In other embodiments, activation can appear as continuous while highlighting can be discrete, i.e., movement is not reflected as flowing from one to the other—instead one option is fully de-highlighted as another is fully highlighted. In still other embodiments, activation can be discrete and highlighting continuous. Combinations not listed herein would be appreciated by one skilled in the art and lack of a description herein does not limit the invention only to the embodiments described.

In some embodiments, activation is determined by the following sequence of steps. In this example, the wrist is used as the activating joint, but any joint in the animation skeleton, or pseudo-joint computed from joints in the skeleton, can be used. Although the activation motion described here is horizontal, activation may be vertical, or may be along the z axis or along any linear combination of axes. All that is needed is that the activation motion direction is sufficiently different from the highlighting motion direction.

If no “initial wrist position” has been recorded, it is determined whether the initial wrist position should be recorded by comparing the horizontal position of the wrist to the horizontal position of a reference point, which has some relation to the user's body. If the wrist is further from the midline of the body than the reference point, the three-dimensional wrist position is recorded as the initial wrist position.

In some embodiments, the reference point is based on a joint in the skeleton or a pseudo-joint computed from joints in the skeleton. For example, the reference point may be based on the shoulder joint on the same side of the body as the wrist being measured. In some embodiments, the reference point is a fixed distance away from a joint in the skeleton or pseudo-joint computed from joints in the skeleton. For example, the reference point may be chosen to be 0.2 meters beyond the shoulder joint on the same side as the wrist being measured, in a direction away from the midline of the body.

Alternatively, the distance of the reference point from a joint in the skeleton or a pseudo-joint computed from joints in the skeleton may be based on the distances between two or more joints in the skeleton. For example, the reference point may be chosen to be beyond the shoulder in a direction away from the midline of the body by half of the distance between the shoulders. Specifically, a player with 30 centimeters between his shoulder and midline would have a reference point of 15 centimeters beyond his shoulder (i.e., outside his torso body on the same side). And a player with 24 centimeters between his shoulder and midline would have a reference point of 12 centimeters beyond his shoulder. Advantageously, using a relative measurement to compute the reference point makes the system more robust to users of different sizes.

Once the initial wrist position is recorded, successive frames of data are interpreted by the system. If the wrist joint is still beyond the reference point (away from the midline of body), or the wrist joint is in front of a second reference point by some threshold amount, the steps are continued. In some embodiments, the second reference point is based on the shoulder joint. In other embodiments, the second reference point is based on one or more other joints in the skeleton, such as the hip joint. If the wrist joint is not beyond the first reference point (that is, it is closer to the midline of the body than the reference point), and the wrist joint is not in front of the second reference point, the initial wrist position is cleared and the tracking begins again. In some embodiments the threshold amount is 0.2 meters. Beneficially, this ensures that the user's hand is in front of them, which tends to reduce false positive interpretations of activation.

For each successive frame of data that is received, the overall x displacement from the initial wrist position to the current wrist position is computed. This value is considered the “swipe distance”.

Also for each successive frame of data that is received, the absolute value of overall y displacement from the initial wrist position is computed. This is called the “y error.” Optionally, the maximum of zero and the overall z displacement from the initial wrist position is computed. This is called the “z error”. Beneficially, clamping the minimum z error to zero avoids penalizing the user for drawing their hand towards their body at the end of the swipe, which is a natural motion that some people make.

Overall error, or “anti-swipe distance,” is computed by combining the y error and the z error. In some embodiments, the z error is ignored. In some embodiments, the y error and z error are added together to produce the anti-swipe distance. In some embodiments, a fraction of the y error and a fraction of the z error are used to compute anti-swipe distance. The maximum anti-swipe distance since recording the initial wrist position is then recorded.

The “total swipe distance” is computed as the sum of the swipe distance and the maximum anti-swipe distance. If the total swipe distance is less than a first threshold (that accounts for minimal movement, or potential noise in the camera input), this frame is skipped, the initial wrist position is cleared, and the tracking begins again. In some embodiments, this threshold is zero meters. Beneficially, this allows the user to continue the activation gesture as long as he stays within a threshold number of degrees of horizontal. For example, if anti-swipe distance comprised 100% of y error, and the threshold is zero meters, the user only needs to keep his swipe within 45 degrees to the horizontal.

If the total swipe distance is greater than the first threshold, but less than a second threshold (the second threshold being the distance necessary to complete the activation), activation of the highlighted item continues. In some embodiments, the second threshold is 0.2 meters. If the total swipe distance is greater than the second threshold, the highlighted item is considered activated.

Scrolling

In addition to providing highlighting and activation from a menu with a fixed number of options, the invention provides an intuitive means of scrolling to additional menu options. In the scenario where there are more choices than available slots in the main menu, certain spatial positions of the person's appendage are reserved for navigating or “scrolling” quickly to menu options that are outside the range of the ones currently presented (and correspondingly scrolling undesired choices out of the current menu). In one embodiment, this is accomplished similarly to determining which menu option is being highlighted, i.e., a scale vector is created for each side from shoulder to pelvis, that scale is projected onto a vertical axis and depending on the location of the user's wrist joint, the invention determines the appropriate scroll speed. Beneficially, the scroll functionality can be built in conjunction with the menu highlighting by assigning the area normally assigned to the top menu option to the active area indicating a scroll up operation, and assigning the area normally assigned to the bottom menu operation to the active area indicating a scroll down operation. In some embodiments, there is also a hysteresis between the menu options area and the scroll areas, i.e., between the top option and the upward scroll zone, and between the bottom option and the downward scroll zone.

FIG. 5A shows one implementation of scrolling. In FIG. 5, options available to scroll into the menu from the top are “Barbaro” and “Alysheba.” The menu options to scroll in from the bottom are “Giacomo,” “Go for Gin,” “Grindstone,” and others. The bottommost menu option is highlighted because the user is scrolling options from beyond the bottom into the menu area. FIG. 5B shows that the user has moved his wrist joint up into the top menu option area and has thus scrolled Barbaro and Alysheba into the menu area.

In one embodiment, the skeletal model range 0.0 to 1.0 described above maps onto the screen space as follows: the value 0.0 is the vertical midpoint of the bottommost menu option and, in the case of a scrolling list, the bottommost menu option is the scroll-down area. Value 1.0 is the vertical midpoint of the topmost menu option, which, in the case of a scrolling list, is the scroll-up area. If the user's wrist joint is exactly at the same height as the shoulder (1.0), the corresponding point in screen space is the midpoint of the topmost menu option.

Scrolling speed can be changed depending on how far outside the 0.0 to 1.0 range the user's wrist joint is. For a scrolling list, in the range 1.0 to 2.0, upwards scroll speed increases (and downward scrolling increases from 0.0 to −1.0). In some embodiments, the speed is increased linearly. For example, the scroll speed ranges from 1 menu option being scrolled into the menu area per second at the shoulder (1.0), to 10 menu options being scrolled in per second at 2.0. In other embodiments, the speed is increased non-linearly. For example, if the wrist joint is in the scrolling area (further than the adjacent option's hysteresis zone), but is less than 1.0, the upward scroll rate would be 1 single-line scroll per second. As the wrist joint ranges from 1.0 to 2.0, however, the scroll rate would increase linearly up to 10 single-line scrolls per second.

Similar principles apply when with respect to scrolling down through options. When the invention determines that the user's arm is at or slightly below the range 0.0, menu options scroll into the menu area at a rate of 1 single-line scroll per second. If the user's wrist joint moves to −1.0, then menu options scroll into the menu area at a rate of 10 single-line scrolls per second.

In both scrolling operations, there is delay built in to ease the user into the scrolling speed. Specifically, in some embodiments, there is a 0.3 second delay between a user's wrist joint entering the active area for scrolling and the actual scrolling of menu options into the menu area. In some embodiments, the scrolling rate gradually increases to the target scrolling rate, rather than jumping directly to the target scrolling rate. This is simply to prevent the user from accidentally crossing the hysteresis threshold and scrolling several options into the menu area that are undesired.

Scroll speed, however, is not limited to having the user reach higher or lower in the scrolling areas. In some embodiments, specific motions can be used to control scroll speed, rather than the position of the user's wrist joint. For example, scroll speed can be controlled by how quickly the user is shaking his hand. In those embodiments, when the user moves his wrist joint into the scroll area, menu options are scrolled slowly into the menu area. If the user shakes his hand while it is in the scroll area, the scrolling speed increases. Correspondingly, if the user then shakes of his hand slowly, the scroll speed decreases. Determining how fast a user shakes his hand can be accomplished in a variety of ways. In some embodiments, inter-frame calculations are performed on the wrist—similar to activation—and only repeated movement within adjacent time frames is determined. Alternatively, in other embodiments, several adjacent frames of the RGB camera and/or the depth camera are compared to determine if the position of the wrist joint (or hand joint) changed quickly across the compared frames, e.g., had a position value that oscillated between two areas over the frames.

In some embodiments, audio feedback can be provided during scrolling, reinforcing the scrolling action the user is selecting. In some embodiments, a sound can be played as each item is scrolled into place, thus producing an increasingly rapid sound effect as scrolling speed increases. In other embodiments, sound effects are not produced on a strictly one-for-one basis as each item is scrolled into place, but can be produced in proportion to the scrolling speed. In some embodiments, the sound can be different depending on scroll direction, so that scrolling up can produce a different set of sound effects than scrolling down. In some embodiments, scroll speeds below a threshold value can produce sound effects on a strictly one-for-one basis as each item is scrolled into place, and above the threshold value, sound effects can be produced in proportion to the scrolling speed. In some embodiments, the sound effects played in proportion to the scrolling speed can be produced by playing a sound loop where the speed or pitch or both speed and pitch are proportional to the scrolling speed.

Viewport Scrolling

The advantages provided by the invention for scrolling additional menu items into a menu display can also apply to cases of scrolling of a viewport over any large data set. In one embodiment, a viewport is displayed on the screen, within which visual data is presented. A 3D skeleton is received from the sensor, and a body-relative scale vector is determined by projecting the vector between two joints onto an axis of motion for the viewport. In some embodiments, the two joints are a shoulder joint and a hip joint on the same side of the body. In some embodiments, the two joints are a shoulder joint and a pseudo-joint computed to approximate the center of the pelvis, however the two joints may be any two joints that are roughly aligned with the axis of motion. In some embodiments the axis of motion for the viewport is vertical, but the axis can be horizontal (where the two joints could be the user's shoulder joints) or any other orientation. The scale vector is assigned a range of values based on the two joints. For example, the projected hip joint can be assigned the value 0.0, and the projected shoulder joint can be assigned the value 1.0.

Next, a value for a “pointing joint” from the 3D skeleton is assigned to the range of values on the projected scale vector. In some embodiments the pointing joint is the wrist joint. For example, if the projected scale vector has a value of 0.0 at the right hip and a value of 1.0 at the right shoulder, and the right wrist is held vertically midway between the hip and the shoulder, the value of the wrist joint would be 0.5.

In some embodiments, the value of the pointing joint is compared to the reference point in the range of values of the projected scale vector. In some of these embodiments, the reference point is the midpoint of the range of values. If the value of the pointing joint is above a threshold distance from the reference point, a scrolling action is executed, the threshold distance providing protection from noisy input. In some embodiments, the threshold distance is a fixed distance, for example 5 cm. In some embodiments, the threshold distance is relative to the projected scale vector, for example 0.1 units. In some embodiments, the rate of scrolling is in proportion to the distance from the reference point. In some embodiments, the rate of scrolling is at one of a fixed number of levels, based on fixed threshold distances of the pointing joint from the reference point.

In some embodiments, the direction of scrolling is based on the direction the pointing joint is from the reference point. For example, if the axis of motion is vertical, and the pointing joint is below the reference point, the viewport is scrolled down, and if the pointing joint is above the reference point, the viewport is scrolled up.

In some embodiments, the scrolling mechanism is applied to two axes of motion for the viewport simultaneously. In some of these embodiments, the two axes are substantially perpendicular to one another. For example, simultaneously with the vertical scrolling, horizontal scrolling may be performed. In some embodiments with horizontal scrolling, the two joints used to produce the scale vector are the two shoulders, and the axis of motion is horizontal. In some embodiments with horizontal scrolling, the reference point is the midpoint between the two shoulders. In other embodiments with horizontal scrolling, reference point is the shoulder on the same side of the body as the pointing joint. In some embodiments applying to two axes of motion simultaneously, the pointing joint is the same for both axes of motion. For example, the viewport can be scrolling over map data. The right wrist is the pointing joint for both horizontal and vertical movement. The viewpoint scrolls over the virtual map in a direction corresponding to the movement of the wrist, and in proportion to the body size as measured along each axis independently.

In some embodiments, rather than positions of joints being used directly, the positions of joints are averaged over time to avoid jitter.

Back Navigation

FIG. 6 shows activation of the “back” functionality, where the user has swiped his left hand from left to right. Correspondingly, the Back ribbon is active (BACK is in yellow lettering) and the Back ribbon is being pulled left to right.

Rather than provide a forward-and-back type functionality from one appendage or that has no relation to the appendage used—as is the case with the “cover flow” in Apple, Inc.'s iTunes—segregating the possible inputs provided by each appendage prevents the system from misinterpreting the user's actions. Specifically, in the example case provided, even in the user moves his left hand up parallel to his right hand and moves it vertically, the input from the left hand will not trigger the highlighting or activation of a menu, because those actions are dedicated to the right hand. Similarly, if the user moves his right hand from left to right, it does not trigger a back action because the back action can only be accomplished using the user's left hand.

Beneficially, in some embodiments, the back button is always present in the same area and the user must highlight and activate the back button in the same manner. This provides a consistent user interface to the user, thereby making the user more comfortable with navigating a menu in a manner he is not accustomed to. In these embodiments, the user moves his hand into the area corresponding to the back area, as if the back area were a bottommost menu option on the left side, before he can make a horizontal left-to-right swipe to activate the back functionality.

User Orientation

In any camera-based input system, it can be hard for the user to know where he is in the camera's field of view, or to know how to position himself in a way that is optimal for the camera. One aspect of the invention assists one or more users in determining where they are in the camera's field of view, where they need to move to be more optimally positioned, and which of the users is considered the active player.

In some embodiments, if the camera system does not detect a user in its field of view, an image from the camera can be projected onto part, or all, of the display screen. This image can be reversed right to left to simulate a mirror. If a user enters the field of view of the camera, the image from the camera can be dimmed or removed, and the outline of the user can be presented instead. This outline can be filled in, and various graphical effects such as textures and lighting can be added to hint at the user's position relative to the optimal position, and to indicate whether this user is considered the active player. For example, the active player can be filled-in in white, while the background scene is rendered in monochrome red. If a second user enters the field of view of the camera, that user's outline can be filled in as well, indicating that they are being tracked. If they are not considered the active user, a different set of graphical effects can be used. For example, a non-active user's outline can be filled in with red, or with a texture indicating that they are not considered by the system to be an active user. In this way, any number of users can enter the field of view and be tracked individually, and the active user can be indicated. In cases where there is more than one active user, all active users can be indicated differently from the non-active users, and they can be distinguished as different players by overlaying different icons, using different textures, labeling the figures on the screen, using different colors, or by any other means familiar to one skilled in the art.

In addition to indicating the presence of users and which user or users are active, the system can reinforce optimal positioning by giving feedback to the user when they step to far to one side or the other, or are too high or too low with respect to the camera angle, or are too close or too far from the camera. For example, as a user begins moving too far to the left, the corresponding edge of the on-screen display can begin to pulse a warning color. In some embodiments, the pulsation begins when the extremity of the user furthest toward that edge of the camera's field of view is within a eighth of the size of the camera's field of view along that dimension. For example, if the camera's field of view is two meters wide, pulsation along the left edge of the on-screen display (from the user's perspective) can begin when the user's left wrist is within 0.25 meters of the left edge of the camera's field of view. In some embodiments, a text message instructing the user is presented. In some embodiments, icons or animations are used to instruct the user on proper placement of their body.

Additional Variations

The examples given herein of a user highlighting and selecting menu choices with his right hand and using his left hand to go back can be adapted for left-handed users as well. For example, the left hand is used for menu highlighting (still up and down) and activation (left to right for left-handed users) and the right hand is used for back functionality (moving right to left).

The use of a skeleton system is also not required. Any system that can detect movement can be used. For example, rather than assigning highlighting and activation to only the right arm, the system can interpret any motion up and down as highlighting and any motion from right to left to be activation. In one embodiment, the system can simply detect the closest point on the user's body to the screen and interpret that to be the user's manipulating hand. In any of these embodiments, the techniques described herein can be used for to highlight any type of menu item, e.g., check boxes, radio buttons, drop downs, and the like.

In some embodiments, execution of game software limits the game platform 120 to a particular purpose, e.g., playing the particular game. In these scenarios, the game platform 120 combined with the software, in effect, becomes a particular machine while the software is executing. In some embodiments, though other tasks may be performed while the software is running, execution of the software still limits the game platform 120 and may negatively impact performance of the other tasks. While the game software is executing, the game platform directs output related to the execution of the game software to a display, thereby controlling the operation of the display. The game platform 120 also can receive inputs provided by one or more players, perform operations and calculations on those inputs, and direct the display to depict a representation of the inputs received and other data such as results from the operations and calculations, thereby transforming the input received from the players into a visual representation of the input and/or the visual representation of an effect caused by the player.

The above-described techniques can be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. The implementation can be as a computer program product, i.e., a computer program tangibly embodied in a machine-readable storage device, for execution by, or to control the operation of, data processing apparatus, e.g., a programmable processor, a computer, a game console, or multiple computers or game consoles. A computer program can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program can be deployed to be executed on one computer or game console or on multiple computers or game consoles at one site or distributed across multiple sites and interconnected by a communication network.

Method steps can be performed by one or more programmable processors executing a computer or game program to perform functions of the invention by operating on input data and generating output. Method steps can also be performed by, and apparatus can be implemented as, a game platform such as a dedicated game console, e.g., PLAYSTATION® 2, PLAYSTATION® 3, PSP® or PSP2® manufactured by Sony Corporation; WII™, NINTENDO 3DS, NINTENDO DS®, NINTENDO DSi™, or NINTENDO DS LITE™ manufactured by Nintendo Corp.; or XBOX® or XBOX 360® manufactured by Microsoft Corp. or special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit) or other specialized circuit. Modules can refer to portions of the computer or game program and/or the processor/special circuitry that implements that functionality.

Processors suitable for the execution of a computer program include, by way of example, special purpose microprocessors, and any one or more processors of any kind of digital computer or game console. Generally, a processor receives instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer or game console are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer or game console also includes, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. Data transmission and instructions can also occur over a communications network. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in special purpose logic circuitry.

To provide for interaction with a user, the above described techniques can be implemented on a computer or game console having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, a television, or an integrated display, e.g., the display of a PSP® or Nintendo DS. The display can in some instances also be an input device such as a touch screen. Other typical inputs include a camera-based system as described herein, simulated instruments, microphones, or game controllers. Alternatively input can be provided by a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer or game console. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input.

The above described techniques can be implemented in a distributed computing system that includes a back-end component, e.g., as a data server, and/or a middleware component, e.g., an application server, and/or a front-end component, e.g., a client computer or game console having a graphical user interface through which a user can interact with an example implementation, or any combination of such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (“LAN”) and a wide area network (“WAN”), e.g., the Internet, and include both wired and wireless networks.

The computing/gaming system can include clients and servers or hosts. A client and server (or host) are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.

The invention has been described in terms of particular embodiments. The alternatives described herein are examples for illustration only and not to limit the alternatives in any way. The steps of the invention can be performed in a different order and still achieve desirable results. Other embodiments are within the scope of the following claims. 

1. A non-transitory computer readable medium storing instructions that, when executed by a computer, cause the computer to: display on a display a plurality of menu items displaced axially along a display axis; receive data from a camera system; determine a first reference point associated with a player's body, the first reference point being based on the data received from the camera system; highlight on the display at least one of the plurality of menu items as a function of the first reference point in relation to a gesture axis that corresponds to the display axis; determine whether the first reference point has moved in a direction substantially perpendicular to the gesture axis; and trigger an activation action based on a determination that the first reference point has moved in a direction substantially perpendicular to the gesture axis.
 2. The non-transitory computer readable medium of claim 1 wherein the first reference point corresponds to a hand of the player.
 3. The non-transitory computer readable medium of claim 1 wherein the gesture axis is substantially vertical.
 4. The non-transitory computer readable medium of claim 1 wherein the gesture axis is substantially parallel to the display axis.
 5. The non-transitory computer readable medium of claim 1 wherein the activation action is triggered based on a distance the first reference point moves in a direction substantially perpendicular to the gesture axis.
 6. The non-transitory computer readable medium of claim 1 further storing instructions that, when executed by the computer, cause the computer to lock the at least one highlighted menu item in response to the first reference point moving a distance in a direction substantially perpendicular to the gesture axis.
 7. The non-transitory computer readable medium of claim 1 further storing instructions that, when executed by the computer, cause the computer to ignore at least one of horizontal and vertical movement of the first reference point as a function of a deviation window.
 8. The non-transitory computer readable medium of claim 1 further storing instructions that, when executed by the computer, cause the computer to determine a measurement of the first reference point relative to a second reference point associated with the player's body.
 9. The non-transitory computer readable medium of claim 8 wherein the second reference point is a shoulder of the player.
 10. The non-transitory computer readable medium of claim 1 further storing instructions that, when executed by the computer, cause the computer to determine a measurement of the first reference point relative to two other reference points associated with the player's body.
 11. The non-transitory computer readable medium of claim 10 wherein the two other reference points are associated with a shoulder and a hip of the player.
 12. The non-transitory computer readable medium of claim 11 further storing instructions that, when executed by the computer, cause the computer to: determine a distance between the shoulder and the hip of the player; divide the distance into a plurality of ranges, each range corresponding to one of the plurality of menu items; and highlight on the display the at least one highlighted menu item as a function of a correspondence of the first reference point to a value within a range from the plurality of ranges.
 13. The non-transitory computer readable medium of claim 1 further storing instructions that, when executed by the computer, cause the computer to: determine whether the first reference point is located in a scroll zone; when the first reference point is in the scroll zone, cause the plurality of menu items to scroll.
 14. The non-transitory computer readable medium of claim 13 further storing instructions that, when executed by the computer cause the computer to indicate the scroll zone on the display.
 15. A computerized method for execution on a game platform, the method comprising: displaying on a display a plurality of menu items displaced axially along a display axis; receiving data from a camera system; determining a first reference point associated with a player's body, the first reference point being based on the data received from the camera system; highlighting on the display at least one of the plurality of menu items as a function of the first reference point in relation to a gesture axis that corresponds to the display axis; determining whether the first reference point has moved in a direction substantially perpendicular to the gesture axis; and triggering an activation action based on a determination that the first reference point has moved in a direction substantially perpendicular to the gesture axis.
 16. The method of claim 15 wherein the first reference point corresponds to a hand of the player.
 17. The method of claim 15 wherein the gesture axis is substantially vertical.
 18. The method of claim 15 wherein the gesture axis is substantially parallel to the display axis.
 19. The method of claim 15 wherein the activation action is triggered based on a distance the first reference point moved in a direction substantially perpendicular to the gesture axis.
 20. The method of claim 15 further comprising locking the at least one highlighted menu item in response to the first reference point moving a distance in a direction substantially perpendicular to the gesture axis.
 21. The method of claim 15 further comprising ignoring at least one of horizontal and vertical movement of the first reference point as a function of a deviation window.
 22. The method of claim 15 further comprising determining a measurement of the first reference point relative to a second reference point associated with the player's body.
 23. The method of claim 21 wherein the second reference point is a shoulder of the player.
 24. The method of claim 15 further comprising determining a measurement of the first reference point relative to two other reference points associated with the player's body.
 25. The method of claim 24 wherein the two other reference points are associated with a shoulder and a hip of the player.
 26. The method of claim 25 further comprising: determining a distance between the shoulder and the hip of the player; dividing the distance into a plurality of ranges, each range corresponding to one of the plurality of menu items; and highlighting on the display the at least one highlighted menu item as a function of a correspondence of the first reference point to a value within a range from the plurality of ranges.
 27. The method of claim 15 further comprising: determining whether the first reference point is located in a scroll zone; when the first reference point is in the scroll zone, causing the plurality of menu items to scroll.
 28. The method of claim 27 further comprising indicating the scroll zone on the display. 